Steel tips are perfectly fine if you're just starting out or only ski a few days a season. They grip adequately on most snow conditions and come standard on budget-friendly poles and rental equipment. For casual skiers, the performance difference won't be very noticeable.
The main trade-off is durability. Steel tips dull faster than carbide and are more likely to bend if you tap rocks. Over time, a worn tip won't bite into icy surfaces as well, which can make pole plants less secure on hardpack. You may eventually need to replace or sharpen them.
If you ski regularly or tackle icy groomers, carbide tips are worth the upgrade—they stay sharp much longer and grip noticeably better. But if you're a beginner still building confidence on the slopes, steel tips will serve you just fine without the extra cost.